Network access devices relying on wired NATs or wireless NATs—sometimes also called Radio Access Technologies (RATs)—have become ubiquitous. As regards RATs, stationary communication networks such as Wireless Local Area Networks (WLANs) as well as mobile communication networks are commonly known.
In the last two decades, digital mobile communication technologies have almost fully replaced analog mobile communication systems, also referred to as first generation systems. With the early digital communication systems (or second generation systems) such as the Global System for Mobile communication (GSM), a wide-spread acceptance and use of mobile telephony services has begun. Today, third generation systems such as the Universal Mobile Telecommunication System (UMTS) as standardized by the 3rd Generation Partnership Project (3GPP) offer a plethora of sophisticated multimedia features and novel mobile applications including, for example, personal navigation via the Global Positioning System (GPS). Fourth generation technologies are already about to enter the standardization phase.
Since the earliest Release 99 of the 3GPP specifications, UMTS uses W-CDMA (Wideband Code Division Multiple Access) as high speed transmission protocol on the air interface. The performance of the W-CDMA-based UMTS standard is extended and improved by a collection of technologies known as High Speed Packet Access (HSPA) protocols. Two different protocols, High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA), have been standardized by 3GPP. HSPDA is part of the UMTS specifications since Release 5, while the specifications for HSUPA are included in Release 6.
A further enhancement of the UMTS standard, Evolved HSPA (eHSPA) or HSPA+, will be introduced with Release 7. Evolved HSPA provides even higher data rates on both the uplink and the downlink using sophisticated technologies such as antenna diversity (Multiple Input Multiple Output, or MIMO) and higher order modulation. While eHSPA still relies on W-CDMA, the Long Term Evolution (LTE) project of 3GPP is defining a new air interface that will be implemented with Release 8 of the 3GPP specifications.
The parallel existence of various 3GPP Releases makes it desirable for a single item of hardware (such as a mobile telephone) to provide support for Radio Access Technologies (RATs) defined in different Releases. Such multi-Release support increases the overall connectivity. As one example, a multi-Release mobile telephone may automatically perform radio access via an “older” Release RAT if the locally available radio network infrastructure is not compatible with a newer Release RAT also supported by the mobile telephone. Then, an automatic hand-over from the older Release RAT to the newer Release RAT is performed as soon as the mobile telephone enters the coverage area of radio network infrastructure supporting the newer Release RAT.
In mobile telephones, support for a new Release (either singly or in combination with support for one or more previous Releases) also requires a new hardware design. As each new Release moves the maximum data rate to a higher limit, the hardware requirements are also becoming increasingly demanding in relation to parameters such as signal processing speed, data storage size, data transfer latency and data throughput. It is evident that the hardware requirements are particularly demanding in case a new hardware design with multi-Release support is desired or if multi-Release support shall at least be a future option for the new hardware design.
Hardware designs for devices supporting high maximum data rates often suffer from a comparatively high data transfer latency and from expensive technological efforts to achieve the necessary data throughput. It has empirically been found that these sufferings can in part be attributed to the internal memory configuration of the devices and in particular the repeated transfer of data between distributed physical memories.